By virtue of such features as light weight, small thickness and low power consumption, liquid crystal display devices have been used in various fields as display devices of OA equipment such as a personal computer, a TV, etc. In recent years, liquid crystal display devices have also been used as display devices of a portable terminal device such as a mobile phone, a car navigation apparatus, a game machine, etc.
In such liquid crystal display devices, in some cases, retardation films are disposed to optically compensate retardation due to birefringence of a liquid crystal layer in a frontal direction and an oblique direction. As such retardation films, there have been proposed retardation films in which, when the refractive indices in an in-plane slow axis direction, an in-plane fast axis direction and a thickness direction are nx, ny and nz, respectively, the in-plane retardation value (also referred to as “in-plane retardation Re” in this specification) defined by (nx−ny)*d or the thickness-directional retardation value (also referred to as “retardation Rth in the thickness direction” in this specification) defined by ((nx+ny)/2−nz)*d is set in various ranges.